include/linux/tcp.h

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Definitions for the TCP protocol.
   7  *
   8  * Version:     @(#)tcp.h       1.0.2   04/28/93
   9  *
  10  * Author:      Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  11  *
  12  *              This program is free software; you can redistribute it and/or
  13  *              modify it under the terms of the GNU General Public License
  14  *              as published by the Free Software Foundation; either version
  15  *              2 of the License, or (at your option) any later version.
  16  */
  17 #ifndef _LINUX_TCP_H
  18 #define _LINUX_TCP_H
  19
  20 #include <linux/types.h>
  21 #include <asm/byteorder.h>
  22
  23 struct tcphdr {
  24         __u16   source;
  25         __u16   dest;
  26         __u32   seq;
  27         __u32   ack_seq;
  28 #if defined(__LITTLE_ENDIAN_BITFIELD)
  29         __u16   res1:4,
  30                 doff:4,
  31                 fin:1,
  32                 syn:1,
  33                 rst:1,
  34                 psh:1,
  35                 ack:1,
  36                 urg:1,
  37                 ece:1,
  38                 cwr:1;
  39 #elif defined(__BIG_ENDIAN_BITFIELD)
  40         __u16   doff:4,
  41                 res1:4,
  42                 cwr:1,
  43                 ece:1,
  44                 urg:1,
  45                 ack:1,
  46                 psh:1,
  47                 rst:1,
  48                 syn:1,
  49                 fin:1;
  50 #else
  51 #error  "Adjust your <asm/byteorder.h> defines"
  52 #endif
  53         __u16   window;
  54         __u16   check;
  55         __u16   urg_ptr;
  56 };
  57
  58 /*
  59  *      The union cast uses a gcc extension to avoid aliasing problems
  60  *  (union is compatible to any of its members)
  61  *  This means this part of the code is -fstrict-aliasing safe now.
  62  */
  63 union tcp_word_hdr {
  64         struct tcphdr hdr;
  65         __u32             words[5];
  66 };
  67
  68 #define tcp_flag_word(tp) ( ((union tcp_word_hdr *)(tp))->words [3])
  69
  70 enum {
  71         TCP_FLAG_CWR = __constant_htonl(0x00800000),
  72         TCP_FLAG_ECE = __constant_htonl(0x00400000),
  73         TCP_FLAG_URG = __constant_htonl(0x00200000),
  74         TCP_FLAG_ACK = __constant_htonl(0x00100000),
  75         TCP_FLAG_PSH = __constant_htonl(0x00080000),
  76         TCP_FLAG_RST = __constant_htonl(0x00040000),
  77         TCP_FLAG_SYN = __constant_htonl(0x00020000),
  78         TCP_FLAG_FIN = __constant_htonl(0x00010000),
  79         TCP_RESERVED_BITS = __constant_htonl(0x0F000000),
  80         TCP_DATA_OFFSET = __constant_htonl(0xF0000000)
  81 };
  82
  83 /* TCP socket options */
  84 #define TCP_NODELAY             1       /* Turn off Nagle's algorithm. */
  85 #define TCP_MAXSEG              2       /* Limit MSS */
  86 #define TCP_CORK                3       /* Never send partially complete segments */
  87 #define TCP_KEEPIDLE            4       /* Start keeplives after this period */
  88 #define TCP_KEEPINTVL           5       /* Interval between keepalives */
  89 #define TCP_KEEPCNT             6       /* Number of keepalives before death */
  90 #define TCP_SYNCNT              7       /* Number of SYN retransmits */
  91 #define TCP_LINGER2             8       /* Life time of orphaned FIN-WAIT-2 state */
  92 #define TCP_DEFER_ACCEPT        9       /* Wake up listener only when data arrive */
  93 #define TCP_WINDOW_CLAMP        10      /* Bound advertised window */
  94 #define TCP_INFO                11      /* Information about this connection. */
  95 #define TCP_QUICKACK            12      /* Block/reenable quick acks */
  96 #define TCP_CONGESTION          13      /* Congestion control algorithm */
  97
  98 #define TCPI_OPT_TIMESTAMPS     1
  99 #define TCPI_OPT_SACK           2
 100 #define TCPI_OPT_WSCALE         4
 101 #define TCPI_OPT_ECN            8
 102
 103 enum tcp_ca_state
 104 {
 105         TCP_CA_Open = 0,
 106 #define TCPF_CA_Open    (1<<TCP_CA_Open)
 107         TCP_CA_Disorder = 1,
 108 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
 109         TCP_CA_CWR = 2,
 110 #define TCPF_CA_CWR     (1<<TCP_CA_CWR)
 111         TCP_CA_Recovery = 3,
 112 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
 113         TCP_CA_Loss = 4
 114 #define TCPF_CA_Loss    (1<<TCP_CA_Loss)
 115 };
 116
 117 struct tcp_info
 118 {
 119         __u8    tcpi_state;
 120         __u8    tcpi_ca_state;
 121         __u8    tcpi_retransmits;
 122         __u8    tcpi_probes;
 123         __u8    tcpi_backoff;
 124         __u8    tcpi_options;
 125         __u8    tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
 126
 127         __u32   tcpi_rto;
 128         __u32   tcpi_ato;
 129         __u32   tcpi_snd_mss;
 130         __u32   tcpi_rcv_mss;
 131
 132         __u32   tcpi_unacked;
 133         __u32   tcpi_sacked;
 134         __u32   tcpi_lost;
 135         __u32   tcpi_retrans;
 136         __u32   tcpi_fackets;
 137
 138         /* Times. */
 139         __u32   tcpi_last_data_sent;
 140         __u32   tcpi_last_ack_sent;     /* Not remembered, sorry. */
 141         __u32   tcpi_last_data_recv;
 142         __u32   tcpi_last_ack_recv;
 143
 144         /* Metrics. */
 145         __u32   tcpi_pmtu;
 146         __u32   tcpi_rcv_ssthresh;
 147         __u32   tcpi_rtt;
 148         __u32   tcpi_rttvar;
 149         __u32   tcpi_snd_ssthresh;
 150         __u32   tcpi_snd_cwnd;
 151         __u32   tcpi_advmss;
 152         __u32   tcpi_reordering;
 153
 154         __u32   tcpi_rcv_rtt;
 155         __u32   tcpi_rcv_space;
 156
 157         __u32   tcpi_total_retrans;
 158 };
 159
 160 #ifdef __KERNEL__
 161
 162 #include <linux/config.h>
 163 #include <linux/skbuff.h>
 164 #include <net/sock.h>
 165 #include <net/inet_connection_sock.h>
 166 #include <net/inet_timewait_sock.h>
 167
 168 /* This defines a selective acknowledgement block. */
 169 struct tcp_sack_block {
 170         __u32   start_seq;
 171         __u32   end_seq;
 172 };
 173
 174 struct tcp_options_received {
 175 /*      PAWS/RTTM data  */
 176         long    ts_recent_stamp;/* Time we stored ts_recent (for aging) */
 177         __u32   ts_recent;      /* Time stamp to echo next              */
 178         __u32   rcv_tsval;      /* Time stamp value                     */
 179         __u32   rcv_tsecr;      /* Time stamp echo reply                */
 180         __u16   saw_tstamp : 1, /* Saw TIMESTAMP on last packet         */
 181                 tstamp_ok : 1,  /* TIMESTAMP seen on SYN packet         */
 182                 dsack : 1,      /* D-SACK is scheduled                  */
 183                 wscale_ok : 1,  /* Wscale seen on SYN packet            */
 184                 sack_ok : 4,    /* SACK seen on SYN packet              */
 185                 snd_wscale : 4, /* Window scaling received from sender  */
 186                 rcv_wscale : 4; /* Window scaling to send to receiver   */
 187 /*      SACKs data      */
 188         __u8    eff_sacks;      /* Size of SACK array to send with next packet */
 189         __u8    num_sacks;      /* Number of SACK blocks                */
 190         __u16   user_mss;       /* mss requested by user in ioctl */
 191         __u16   mss_clamp;      /* Maximal mss, negotiated at connection setup */
 192 };
 193
 194 struct tcp_request_sock {
 195         struct inet_request_sock req;
 196         __u32                    rcv_isn;
 197         __u32                    snt_isn;
 198 };
 199
 200 static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
 201 {
 202         return (struct tcp_request_sock *)req;
 203 }
 204
 205 struct tcp_sock {
 206         /* inet_connection_sock has to be the first member of tcp_sock */
 207         struct inet_connection_sock     inet_conn;
 208         int     tcp_header_len; /* Bytes of tcp header to send          */
 209
 210 /*
 211  *      Header prediction flags
 212  *      0x5?10 << 16 + snd_wnd in net byte order
 213  */
 214         __u32   pred_flags;
 215
 216 /*
 217  *      RFC793 variables by their proper names. This means you can
 218  *      read the code and the spec side by side (and laugh ...)
 219  *      See RFC793 and RFC1122. The RFC writes these in capitals.
 220  */
 221         __u32   rcv_nxt;        /* What we want to receive next         */
 222         __u32   snd_nxt;        /* Next sequence we send                */
 223
 224         __u32   snd_una;        /* First byte we want an ack for        */
 225         __u32   snd_sml;        /* Last byte of the most recently transmitted small packet */
 226         __u32   rcv_tstamp;     /* timestamp of last received ACK (for keepalives) */
 227         __u32   lsndtime;       /* timestamp of last sent data packet (for restart window) */
 228
 229         /* Data for direct copy to user */
 230         struct {
 231                 struct sk_buff_head     prequeue;
 232                 struct task_struct      *task;
 233                 struct iovec            *iov;
 234                 int                     memory;
 235                 int                     len;
 236         } ucopy;
 237
 238         __u32   snd_wl1;        /* Sequence for window update           */
 239         __u32   snd_wnd;        /* The window we expect to receive      */
 240         __u32   max_window;     /* Maximal window ever seen from peer   */
 241         __u32   mss_cache;      /* Cached effective mss, not including SACKS */
 242         __u16   xmit_size_goal; /* Goal for segmenting output packets   */
 243         /* XXX Two bytes hole, try to pack */
 244
 245         __u32   window_clamp;   /* Maximal window to advertise          */
 246         __u32   rcv_ssthresh;   /* Current window clamp                 */
 247
 248         __u32   frto_highmark;  /* snd_nxt when RTO occurred */
 249         __u8    reordering;     /* Packet reordering metric.            */
 250         __u8    frto_counter;   /* Number of new acks after RTO */
 251         __u8    nonagle;        /* Disable Nagle algorithm?             */
 252         __u8    keepalive_probes; /* num of allowed keep alive probes   */
 253
 254 /* RTT measurement */
 255         __u32   srtt;           /* smoothed round trip time << 3        */
 256         __u32   mdev;           /* medium deviation                     */
 257         __u32   mdev_max;       /* maximal mdev for the last rtt period */
 258         __u32   rttvar;         /* smoothed mdev_max                    */
 259         __u32   rtt_seq;        /* sequence number to update rttvar     */
 260
 261         __u32   packets_out;    /* Packets which are "in flight"        */
 262         __u32   left_out;       /* Packets which leaved network */
 263         __u32   retrans_out;    /* Retransmitted packets out            */
 264 /*
 265  *      Options received (usually on last packet, some only on SYN packets).
 266  */
 267         struct tcp_options_received rx_opt;
 268
 269 /*
 270  *      Slow start and congestion control (see also Nagle, and Karn & Partridge)
 271  */
 272         __u32   snd_ssthresh;   /* Slow start size threshold            */
 273         __u32   snd_cwnd;       /* Sending congestion window            */
 274         __u16   snd_cwnd_cnt;   /* Linear increase counter              */
 275         __u16   snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
 276         __u32   snd_cwnd_used;
 277         __u32   snd_cwnd_stamp;
 278
 279         struct sk_buff_head     out_of_order_queue; /* Out of order segments go here */
 280
 281         __u32   rcv_wnd;        /* Current receiver window              */
 282         __u32   rcv_wup;        /* rcv_nxt on last window update sent   */
 283         __u32   write_seq;      /* Tail(+1) of data held in tcp send buffer */
 284         __u32   pushed_seq;     /* Last pushed seq, required to talk to windows */
 285         __u32   copied_seq;     /* Head of yet unread data              */
 286
 287 /*      SACKs data      */
 288         struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
 289         struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
 290
 291         struct tcp_sack_block recv_sack_cache[4];
 292
 293         /* from STCP, retrans queue hinting */
 294         struct sk_buff* lost_skb_hint;
 295
 296         struct sk_buff *scoreboard_skb_hint;
 297         struct sk_buff *retransmit_skb_hint;
 298         struct sk_buff *forward_skb_hint;
 299         struct sk_buff *fastpath_skb_hint;
 300
 301         int     fastpath_cnt_hint;
 302         int     lost_cnt_hint;
 303         int     retransmit_cnt_hint;
 304         int     forward_cnt_hint;
 305
 306         __u16   advmss;         /* Advertised MSS                       */
 307         __u16   prior_ssthresh; /* ssthresh saved at recovery start     */
 308         __u32   lost_out;       /* Lost packets                 */
 309         __u32   sacked_out;     /* SACK'd packets                       */
 310         __u32   fackets_out;    /* FACK'd packets                       */
 311         __u32   high_seq;       /* snd_nxt at onset of congestion       */
 312
 313         __u32   retrans_stamp;  /* Timestamp of the last retransmit,
 314                                  * also used in SYN-SENT to remember stamp of
 315                                  * the first SYN. */
 316         __u32   undo_marker;    /* tracking retrans started here. */
 317         int     undo_retrans;   /* number of undoable retransmissions. */
 318         __u32   urg_seq;        /* Seq of received urgent pointer */
 319         __u16   urg_data;       /* Saved octet of OOB data and control flags */
 320         __u8    urg_mode;       /* In urgent mode               */
 321         __u8    ecn_flags;      /* ECN status bits.                     */
 322         __u32   snd_up;         /* Urgent pointer               */
 323
 324         __u32   total_retrans;  /* Total retransmits for entire connection */
 325         __u32   bytes_acked;    /* Appropriate Byte Counting - RFC3465 */
 326
 327         unsigned int            keepalive_time;   /* time before keep alive takes place */
 328         unsigned int            keepalive_intvl;  /* time interval between keep alive probes */
 329         int                     linger2;
 330
 331         unsigned long last_synq_overflow;
 332
 333 /* Receiver side RTT estimation */
 334         struct {
 335                 __u32   rtt;
 336                 __u32   seq;
 337                 __u32   time;
 338         } rcv_rtt_est;
 339
 340 /* Receiver queue space */
 341         struct {
 342                 int     space;
 343                 __u32   seq;
 344                 __u32   time;
 345         } rcvq_space;
 346
 347 /* TCP-specific MTU probe information. */
 348         struct {
 349                 __u32             probe_seq_start;
 350                 __u32             probe_seq_end;
 351         } mtu_probe;
 352 };
 353
 354 static inline struct tcp_sock *tcp_sk(const struct sock *sk)
 355 {
 356         return (struct tcp_sock *)sk;
 357 }
 358
 359 struct tcp_timewait_sock {
 360         struct inet_timewait_sock tw_sk;
 361         __u32                     tw_rcv_nxt;
 362         __u32                     tw_snd_nxt;
 363         __u32                     tw_rcv_wnd;
 364         __u32                     tw_ts_recent;
 365         long                      tw_ts_recent_stamp;
 366 };
 367
 368 static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk)
 369 {
 370         return (struct tcp_timewait_sock *)sk;
 371 }
 372
 373 #endif
 374
 375 #endif  /* _LINUX_TCP_H */